[libvirt] [PATCH 5/5] qemuBuildMemoryBackendProps: Get pagesize early

[Ján Tomko]

On Mon, Apr 01, 2019 at 04:04:37PM +0200, Michal Privoznik wrote:
>https://bugzilla.redhat.com/show_bug.cgi?id=1693066
>
>Up until memfd introduction (in 24b74d187ca) we did not need to
>know @pagesize because qemuGetDomainHupageMemPath() could deal
>with it being zero (value of zero means use the default hugetlbfs
>mount). But since for memfd we are not passing a path to
>hugetlbfs mount rather the page size value we need to know its
>value upfront.

This phrasing makes it seem like getting the pagesize is being moved,

>
>Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
>---
> src/qemu/qemu_command.c                       | 14 +++++++
> ...memory-default-hugepage.x86_64-latest.args | 37 ++++++++++++++++
> .../memfd-memory-default-hugepage.xml         | 42 +++++++++++++++++++
> tests/qemuxml2argvtest.c                      |  1 +
> .../memfd-memory-default-hugepage.xml         |  1 +
> tests/qemuxml2xmltest.c                       |  3 ++
> 6 files changed, 98 insertions(+)

but there are no deletions. I'd expect that now it will no longer be
needed in qemuGetDomainHupageMemPath (sic).

> create mode 100644 tests/qemuxml2argvdata/memfd-memory-default-hugepage.x86_64-latest.args
> create mode 100644 tests/qemuxml2argvdata/memfd-memory-default-hugepage.xml
> create mode 120000 tests/qemuxml2xmloutdata/memfd-memory-default-hugepage.xml
>
>diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>index f81d20e5f7..ba1b56c2da 100644
>--- a/src/qemu/qemu_command.c
>+++ b/src/qemu/qemu_command.c
>@@ -3547,6 +3547,20 @@ qemuBuildMemoryBackendProps(virJSONValuePtr *backendProps,
>         pagesize = 0;
>         needHugepage = false;
>         useHugepage = false;
>+    } else if (pagesize == 0) {
>+        virHugeTLBFSPtr p;
>+
>+        if (!cfg->nhugetlbfs) {
>+            virReportError(VIR_ERR_INTERNAL_ERROR,
>+                           "%s", _("hugetlbfs filesystem is not mounted "
>+                                   "or disabled by administrator config"));
>+            goto cleanup;
>+        }
>+
>+        if (!(p = virFileGetDefaultHugepage(cfg->hugetlbfs, cfg->nhugetlbfs)))
>+            p = &cfg->hugetlbfs[0];
>+
>+        pagesize = p->size;

Given how big and beautiful qemuBuildMemoryBackendProps has become,
this would look nicer in another wrapper.

With the corresponding deletions in qemuGetDomainHupageMemPath:
Reviewed-by: Ján Tomko <jtomko at redhat.com>

Jano
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